paymentPass key in PKPaymentToken object

Does anyone has experience with this field? On Apple dev portal it is described as: "Use this property to detect your own custom-branded credit or debit cards. For example, you could provide a discount whenever a customer uses your store-branded credit card."

Is this just information field that such pass has been used by Customer?

This key contains information about a card that is provisioned into the Apple Pay Wallet, if, when that card is provisioned into the Apple Pay Wallet, your App Id is included. This allows your iOS app to identify that the consumer has one of your private label or co-branded cards in the wallet and perform business logic based upon that.